1. Field of the Invention
This invention is directed a beverage brewing system, and in particular, to a brewing system for making hot beverages such as coffee, tea, coco, milk, and soup.
2. Background of the Invention
There are many ways to brew coffee including drip and French press methods. Recently, brewing coffee through a single-serve cartridge has become popular for its convenience and a variety of coffee flavors which are offered. Single-serve cartridges are packed with premeasured coffee grind which can be inserted into a brewer to inject hot water into the cartridge to brew the coffee. Like any other beverages, one of the important criteria for a success of the beverage is its taste, and coffee is no different. In this regard, the Coffee Brewing Center (CBC) during the 1960's, led by Dr. Earl Lockhart, has done a lot of research in understanding the physics and science behind what constitutes a good tasting coffee. The CBC has come up with what is called the “Coffee Brewing Control Chart” like the one shown in FIG. 1, which provides a graphical representation of strength, extraction and brew formula in an easy to read format.
According to the chart shown in FIG. 1, an ideal tasting coffee is obtained when there is a good combination of strength and extraction. Strength is also referred to as total dissolved solids (“TDS”), and the ideal TDS level is 1.15%-1.35%. For example, TDS level of 1.00% means there is 1.00% of coffee concentration and the remaining 99.00% is water in the cup. According to the chart, coffee having a TDS level below 1.15% may taste weak; while coffee having a TDS level above 1.35% may taste too strong. As a reference, coffee from a traditional coffee house, such as Starbucks®, may have a TDS level from about 1.20% to about 1.35%. In practice, many consumers may find that a cup of coffee with a TDS level from about 0.80% to 1.00% to be mild and acceptable taste; while a TDS level from about 1.00% to about 1.15% to be regular strength taste; and a TDS level from about 1.15% to about 1.35% to be a strong coffee taste. The TDS level may be measured using a number of different instruments such as hydrometers, conductivity, Brix and moisture microwave. In particular, a conductivity meter measures the amount of coffee flavoring material based on its conductivity across a coffee infusion.
The chart in FIG. 1 also indicates that the ideal extraction level for coffee is 18%-22%. Extraction means amount of coffee that has dissolved from the coffee grind into the coffee drink. For example, if 10 grams of coffee grind is brewed, and after the brewing there is 8.0 grams of coffee grind left, then the extraction level is 20% because 2 grams or 20% of the coffee grind dissolved into coffee. Extractions below 16% may indicate a coffee taste that is under-developed such that it may have a weak peanut-like flavor, while extractions over 22% may indicate a coffee taste that is over-extracted so it may taste bitter.
Many hot beverages, such as coffee and tea, are now provided in single serve packs which can be inserted into a brewer to inject hot water into the pack to brew hot beverages. For instance, US. Patent Application Publication No. 2005/0051478 entitled BEVERAGE FILTER POD by Karanikos et al. (the “'0051478 Application”), which is hereby incorporated by reference, describes a beverage filter cartridge having a cup like container where the interior is divided into two chambers by a cup-shaped filter element: a first chamber inside the filter and a second chamber located between the filter bottom and the container bottom. The upper rim of the filter is joined at the upper rim of the container side wall, and the filter side wall has exterior channels that face the container side wall and lead downwardly from the peripheral juncture to the second chamber. The filter sidewall is folded to provide exterior channels. And according to the '0051478 Application, during the brewing cycle, the channels provide a passageway for beverage to permeate from the first chamber to the second chamber, and in so doing, improve the full saturation of the beverage grind in areas adjacent to the container side wall.
A beverage grind, such as grinded coffee, is poured into the first chamber, and a cover, such as an aluminum foil, is used to seal the container. An input needle can pierce through the cover to inject hot water into the first chamber to mix with the beverage grind to produce a beverage. The filter element is permeable to allow liquid beverage to pass therethrough while retaining the granular beverage grind within the filter. The beverage passes through the filter via the exterior filter channels, and into the second chamber. An output needle can pierce the bottom of the container to allow the beverage to flow out from the second chamber. While the cartridge described in the '0051478 Application is able to brew a sufficient cup of coffee, the cup size of the coffee is limited because there is a limit as to how much coffee grind the filter can hold.
To brew a bigger cup of coffee, US. Patent Application Publication No. 2010/0303964 entitled CARTRIDGE WITH FILTER GUARD by Beaulieu et al. (the “'0303964 Application”), which is hereby incorporated by reference, discloses a more elongated filter compared to the filter disclosed in the '0051478 Application such that the space in the second chamber is minimized. With a bigger filter, more coffee grind may be inserted into the cartridge to brew a bigger and/or stronger cup of coffee. In order to protect the filter from the output needle piercing through the bottom of the filter, a filter guard is provided between the filter and the bottom of the cartridge so that the filter guard makes contact with the output needle to protect the filter. While providing a larger filter to hold more coffee grind somewhat enabled brewing a stronger tasting coffee or a larger cup of coffee, coffee made from the cartridge generally described in the '0303964 Application resulted in TDS levels of about 0.95%, which may be considered weak according the chart shown in FIG. 1. Accordingly, there still is a need to brew stronger tasting coffee using a single-serve cartridge.
As of 2013, the market leader of single-serve cartridge platform in North America is Green Mountain Coffee Roasters®, which sells its single-serve platform under the Keurig® brand name, collectively referred to as Keurig®. Keurig® offers over 200 varieties of single-serve cups, also known as K-Cup®, which works with several of Keurig's® brewers offered in the market today. There is estimated to be over 12 million U.S. households with Keurig® brewers in use largely due to its convenience where a single cup of coffee can be made without much of a cleanup. A good example of types of brewers offered by Keurig® is generally described in U.S. Pat. No. 7,347,138, which is incorporated by reference.
FIG. 1B is a copy of FIG. 3 of the U.S. Pat. No. 7,347,138. The brewer 10 includes a brew chamber 18 comprised of a cartridge receptacle 20 and a lid 22. The receptacle 20 has a removable holder 23 configured and dimensioned to receive a beverage filter cartridge 24. The holder 23 has a needle at the bottom to pierce through the bottom of the cartridge when the cartridge is pressed down into the holder. The cartridge 24 includes an outer container internally subdivided by a paper filter into two compartments: top and bottom compartments. The top compartment is defined by the shape of paper filter to hold coffee grind within the paper filter. The bottom compartment is a remaining empty space with enough space so that the bottom needle does not pierce the paper filter in order to prevent the coffee grind from washing out during the brewing process.
The holder 23 is removable so that it may be easily cleaned. One of the common elements of the brewers offered by Keurig® is that they all utilize essentially the same holder 23. The holder 23 is configured such that when the cartridge 24 is inserted into the holder 23, the cartridge 24 substantially fills the void within the holder 23 such that there is little gap between the holder 23 and the cartridge 24. This means that the outer shape of the cartridge 24 is constraint by the holder 23 such that cartridge 24 may not be enlarged, which means that there is a limit as to how much coffee grind that can be packed within the paper filter in the cartridge 24. As discussed above, without being able to enlarge the cartridge, only other option is to enlarge the paper filter as much as possible to hold more coffee grind to make a stronger cup of coffee, but doing so lowers the paper filter closer to the bottom needle, which increases the risk of the bottom needle piercing the paper filter. As discussed above, the cartridge disclosed in the '0303964 Application utilizes a filter guard to protect the paper filter from the bottom needle. While the cartridge disclosed in the '0303964 Application can hold more coffee grinds, there is still a limitation due to the fixed outer size of the cartridge 24. As such, there is a need to brew a stronger and bigger cup of coffee when utilizing the Keurig's® brewers.
There are many factors that can determine the taste of coffee; however, the temperature and flow rate of the water passing through the coffee grind can have significant impact on the coffee taste. In general, water temperature between 190-205° F. may be considered a desirable temperature range to brew a good balance tasting coffee. For instance, if the water temperature is below the desired temperature, the coffee may be under-extracted such that the coffee may taste sour. Conversely, if the water temperature is above the desired temperature, the coffee may be over-extracted such that the coffee may taste bitter. With regard to the flow rate, if the hot water passes through the coffee grind too quickly, then the coffee may be under-extracted; however, if the flow rate is too slow, then the coffee may be over-extracted. As such, there is a need for a brewer that can more precisely control the temperature and flow rate of the water.
Another concern is when the single-serve beverage cartridges are offered in commercial settings such as in offices and food service industry. In commercial settings, such as in the office services, the beverages may be serviced by a professional catering service that periodically restock the inventory of beverage cartridges at the offices. This, however, can be a time consuming process, since the professional catering service may need to contact the office manager prior to visiting to get an inventory of beverage cartridges it needs to restock the cartridges. This means that someone from the office may need to manually count the inventory of cartridges it has or does not have, and pass the information to the catering service. Alternatively, the catering service may need to carry the inventory with the truck and driver, and have the driver manually count the inventory, and restock the office. All of these manual operations may be an inefficient way of restocking the beverage cartridges. As such, an improved inventory management system is needed.
The single-serve beverage platform is largely a razor and razor blade business model, where the catering business may offer the brewer for free or at a low price with the understanding that the office customer will purchase the cartridges from the catering service. In certain situations, however, the office may purchase unauthorized cartridges from less expensive retailer to save costs. Unfortunately, such unauthorized purchase of the cartridges can have negative financial impact on the catering business. As such, there is a need to improve the inventory management of the cartridges.